Electric toaster



March 11, 1941. M. IRELAND 2,234,7 4

ELEC'I'RI C TOASTER Filed Nov. 25, 1955 4 Sheets-Sheet l IN V ENTOR. MURRHY [REL/IND ATTORNEY.

March 11, 1941.

M. IRELAND 2,234,764

ELECTRIC TOASTER Filed' Nov. 25, 1935 4 Sheets-Sheet 2 I INVENTOR. 23 M m7 m5; Map ay [QELHND 3H ATTORNEY.

March 1 L WM M. IRELAND ELECTRIC TOASTER Filed NOV. 25, 19

55 4 Sheets-Sheet 3 27 INVENTOR. MuR/em [REL/5M3 BY W Wf ATTORNEY.

Marh 11, 1941. M. IRELAND 1 2,234, 764 ELECTRIC TOASTER Filed Nov. 25, 1935 4 Sheets-Sheet 4 INVENTOR. MURRAY -fa mwp A TTORNE Y.

ill

.enteol Stiller. H, 1941 ITED STATES ELECTRIC TOASTER Murray Ireland, St. Paul, Minn,

assignor to McGraw Electric Company, Chicago, 111., a corporation of Delaware Application November 25, 1935, Serial No. 51,397

19 Claims.

My invention relates to electric cooking devices and particularly to electric toasters.

An object of my invention is to provide a relatively simple thermally actuable timing control means for a cooking device adapted to cook successlve portions of food.

Another object of my invention is to provide a relatively simple thermal timer for determining the length of time of a cooking operation in a cooking appliance.

Another object of my invention is to provide a thermally actuable timer comprising a single thermal element, to determine the length of time of a cyclic cooking operation.

Another object of my invention is to provide a simple thermal timing mechanism for a recurring short-time'cooklng cycle or operation, embodying a bimetal bar occupying substantially the same position at the beginning or each cooking operation and moving away from and back to said position during the cooking cycle.

Another object of my invention is to provide a thermal timing means for an electric cooker such as a toaster, embodying a bimetal element,

. means to thermally energize the same at the be-- ginning of a cooking cycle or operation and then to thermally deenergize the same, and means operatlvely engaged by the bimetal element after being thermally decnergized to terminate the cooking operation.

llnother object of my invention is to provide a thermal timing means for an electric cooking appliance embodying means to compensate for increase in temperature of the appliance.

Uther objects of my invention will either be pointed out during the course of the description of one embodiment of my invention, or will be apparent from such description.

in practicing my invention I provide a cooking appliance, such as an electric toaster comprising a frame or casing, one or more electric heating elements therein, a bread slice support springbiased to non-toasting position, a control switch for the heating elements biased to open position,

a lnanually-actuable means to move the bread slice support to toasting position and the control switch to closed position, and a latch to hold these elements in their actuated positions. 'A thermal element, which may be in the form of a biinetal member of U-shape, has a, heating circuit closely operatively associated therewith, which heating circuit is energized by the manually actuable means. The bimetal element moves or warps first in one direction to deenerglze its heating circuit and then in the opposite direction to finally effect release of the latch to thereby end the toasting operation.

In the drawings,

Figure 1 is a view, in vertical longitudinal sec-' tion, through a toaster embodying my invention, taken on the line I--I of Fig. 2,

Fig. 2 is a bottom plan view of the structure shown in Fig. 1, with the bottom cover removed,

Fig. 3 is a view in vertical longitudinal section therethrough, taken on the line III-III of Fig. 2,

Fig. 4 is a, view in vertical lateral section therethrough, taken on the line IV-IV of Fig. 1,

Fig. 5 is a fragmentary vertical sectional view taken on the line V--V of Fig. 1,

Fig. 6 is a fragmentary view in vertical longil5 tudinal section, taken on the line VI--VI of Fig.

4, the front part only of the assembly being shown,

Fig. 7 is a view similar to only a portion thereof and ticularly the control switch ate operative positions,

Fig. 8 is a view similar to Fig. 7, but showing the control switch parts in final operative positions,

Fig. 9 is a fragmentary view in vertical longitudinal section line IX-IX of Fig.

Fig. 6, but showing showing more par- 20 parts in intermeditaken on the 4, the front part only being shown,

Fig. 10 is a fragmentary view in vertical longitudlnal section taken on the line X--X of Fig. 4, the front portion only of the assembly being shown,

Fig. 11 is a view similar to Fig. 9, but showing only a. portion thereof and showing more particularly the movable parts in actuated position,

Fig. 12 is a diagram of connections which I may use in my improved toaster, and

Fig. 13 is a view in perspective showing a modified form of thermal element and heating circuit.

While my invention is particularly applicable to electric toasters, I do not desire to be limited to such use, since the inventive concept may be embodied in other equivalent structures operative for the same general purpose and in the same manner, a toaster being only one form of device which may be advantageously .controlled to obtain similar or the same results in each cycle or operation of the device.

It is obvious that the cooking of a roast of meat involves in general the raising of the tem-- perature around the roast to a suitable value and then the maintenance thereof at that value for a length of time suiliclent to cook the meat to thedesireddegree, an operation requiring an hour or more. The toasting of a single slice of bread slices of bread involves substantially the same process. namely the raising of the temperature of the structure and therefore of the slice of slices ofbread (and more particularly of the surface thereof) and when the temperature of thesurface of a slice of bread has reached a. predetermined value, the toasting operation may be terminated. Ifa reasonable amount of electric energy is translated into heat, it is possible to complete such a toasting cycle in a relatively short time, which time may be on the order of slightly over one minute, and it is therefore obvious that when a single thermal element is used as a timer; it must'operate through a cycle of movement inorder that it shall properly control the length of time of a toasting operation and be ready for a successive operation immediately, which means that the thermal element must move first in one direction and then in the reverse direction to substantially its initial posi- It is obvious that the toaster structure will experience a 'rise in temperature if it is used cyclically and repeatedly, which action is not,

present to such an extent where the length of time is on the order of several hours. Irrespective of the temperature of the toaster assembly,

frame or casing, the temperature of a slice ofbread placed in the toaster to be toasted is substantially that of the room in which the toasting operation is taking place. It is therefore desirable that the thermal mass of the toaster assembly be made as small as is consistent with other requirements in order that the effect of the relatively cool slice of bread upon the thermal timing means shall be as great as possible in order that the same may operate properly within the relatively short period of time required by the toasting operation.

Referring to the various figures of the drawings, I have there illustrated a vertical toaster structure designated generally by the numeral 2|, which structure or assembly may include a base 23 which may have a depending annular flange 25 to provide a relatively shallow hollow space therebelow, the bottom of which may be closed by a bottom plate 21. Supporting members 29 of suitable heat-insulating material, such as a molded composition, may be secured to the plate 21.

The assembly 2| includes also an outer casing 3| which may be of substantially rectangular shape in contour and may be made of a single metal stamping formed to the desired shape and contour to provide a pleasing external appearance. A top cover member 33 is also associated with the structure and may be secured to the' upper edge of the outer casing 3| in any suitable or desired manner. It is to be understood that any suitable or desired means for securing the casing 3| at its lower edge to the upper surface of the base 23 may be employed and as such mechanical means constitute no part of my present invention, they have not been shown or described in detail. V

As an operative device constructed by me was applied to or embodied in a two slice vertical toaster, I have shown such a two slice toaster in the drawings and it is to be understood that or the simultaneous toasting of a plurality of wound thereon a suitable resistor wire or strip 39 in a manner well known-in the art, the ends of the resistor in each heating element 35 being connected to terminal members II and 43 located adjacent the bottom end or ends of the sheets of 6 electric insulating material 31. I may connect all of these resistor members in parallel circuit relation with each other by means of laterallyextending studs or rods 45 and 41, although this again constitutes no part of my present invention'.

The top wall of the base is provided with a pair of openings 49 and 5! therein, portions of the edges of the wall being turned up as shown at 53 and 55 in Fig. 1 of the drawings to provide means for holding the lower edges of the sheets 31 in proper operative positions.

A top plate and guard wire support 51 is provided at the upper end of each of the respective cooperating pairs of heating elements, which 20 guard wire support is provided with a longitudinally extending opening 59 therein through which a slice of bread may be inserted into the toaster structure and be withdrawn therefrom after it' has been toasted. The cover 33 is provided with a registering opening 59a.

In order that a slice of bread may be held out of contacting engagement with the resistor wires or strips 39, I provide a plurality of depending guard wires St between the slice of bread and the resistor. The upper ends of the respective guard wires 6| are bent over and then downwardly into substantially hook shape, extending through openings in the top plate or guard wire support, the downwardly extending top portion assisting also in holding the upper end of the respective heating elements in their proper operative positions. a

' As it is desired to move the slice or slices of bread from a non-toastin position, that is where at least part of the slice .of bread projects from the casing, to a toasting position where all of the slice-of bread is located within the casing, I provide a bread slice support 63 between each pair of cooperating heating elements, which bread slice support extends substantially horizontally and is vertically movable between spaced sets of guard wires 6| which extend through openingsin the bread slice support.

The bread slice supports have a part thereof extending forwardly through vertically extending slots 65 in an intermediate front wall 61. An intermediate rear wall 69 is provided inside of the casing, the front and rear intermediate inner walls 61 and 69 being connected together and spaced apart by a plurality of horizontally extending rods or bolts 1| which have nuts 13 threaded thereon outside of the respective intermediate walls. The rear end of the respective supports 63 may be extended outwardly through vertical slots 15 in the rear wall 69.

Means for effecting vertical movement of the bread slice supports includes a plurality of vertically extending guide rods Hand 19, one pair for each bread slice support. The lower ends of these shafts may be extended through the top wall of the base 23 at the front part thereof,

while the upper ends thereof may be located either in forwardly extending portions 8| of the top plate, as shown in Fig. 3 of the drawings, or in a spacer bar 85 which extends in a substantially horizontal direction and is interlocked with the upper end of the rods 11 and 19 whereby it serves to hold these rods in proper horizontally spaced positions as well as serving to stiffen and Iii) assay hold the two guard wire supports in desired spaced positions in the assembly. The bread slice supports have secured thereto vertically-extend ing plates 81 whose upper and lower ends extend laterally therefrom and are provided with buslilugs 89 through which the rods 11 extend.

A handle support bracket SI, of plate shape, has upper and lower guide rollers 93 rotatably supported thereon, which rollers are adapted to engage the shafts 19. A handle support 95 is carried by the handle support bracket and extends forwardly thereof and may have an actu ating knob or handle 91 secured thereto, which handle may be made oi heat-insulating material, to be operated by a user 01' the toaster.

An additional guide roller 99 is mounted on one of the bread slice supports and is shown particularly in the left hand upper corner of Fig. 4 of the drawings.

The left hand member '81 carries a switch actuator plate IOI which has an angularly extending slot ili2 therein whose purpose will hereinafter be described. The plate is pivotally mounted on member 81 as by a pivot pin I93, and a spring I94 biases it to the right, as seen in Fig. 1, a stop pin I 0411 limiting its clockwise turning movement.

A control switch for the cooking appliance includes a fixedly supported contact member I95 which is insulatedly mounted on the front inner wall 61 near the lower edge thereof, and an intermediate contact member I01 which is supported by a spring I99 which normally biases the contact member I01 away from the fixed contact member I05. The switch includes also a contact member III mounted on a pivotally supported arm II3 which is mounted on a bracket III and carried by a pivot pin III. The upper end of arm i I3 has a laterally extending pin I I mounted thereon which extends into the slot I02 in the plate II. It is evident that when the bread slice support is moved downwardly by pressure on the handle 91, the plate IIII will move with it and the pin II9 will be moved to the right as seen particularly in Fig. 6, the drawings, whereby to move contact I I I- to the left and initially into engfiement with spring supported contact member i Means for biasing the bread slice support to its upper or non-toasting position includes a bell crank lever I2I comprising a substantially horizontally-extendin arm I23 and a substantially vertically depending arm I25, the bell crank lever being pivoted at I21 adjacent the rear end of the toaster structure on any suitable support such as a pin I29 which may be supported by bent-out brackets I3I integral with the rear wall 69. The forward end of arm I23 is provided with a slot I33 to cooperate with a horizontally extending shaft I35 carried by the bread slice supports. A coil spring I31 is located below the base 23 and has one end thereof hooked to the lower end of depending arm I25 and the other end hooked into any one of a plurality of hook portions I39 provided in the forward portion of the top wall of base 23.

Means for latching the control switch in closed position and the bread slice support in its toasting position may include a latch arm I which is carried by the right hand member 81 at its lower end, the latch I4I being generally in the shape of an arcuate lever pivotally supported intermediate its ends and having a hook portion I43 at its lower end which is adapted to cooperate with a latch plate I45 secured to the bottom surface of base 23 adjacent an opening I41 therein described. Means for releasing the latch may include a coil I49 which is supported in substantially vertical position in a metal frame II at the forward part of the assembly and which coil is adapted to energize a movable armature core I53 having depending therefrom a guide bar I55 to which is secured a laterally extending latch release rod I51 which is adapted to engage the upper portion of latch i4i when the armature I53 is energized and moved in a substantially upwardly direction. Rod i5? is mounted for limited pivotal movement in clockwise direction from the position shown in Figure 12 and overlies the latch I49 when armature I53 is in uppermost position, whereby this rod may pass downwardly past latch I4I without affecting the same when it is in latched position, as will be readily apparent to those skilled in the art.

I will now describe the mechanism constituting more particularly my invention and which embodies a cyclically operating thermal element which normally occupies or is located in a predetermined position, which is moved therefrom in one direction by warping because being heatenergized by a suitable heating circuit, which deenergizes the heating circuit and then cools and moves in the opposite direction to return to substantially its normal initial position where it cooperates with other means to energize the latch-releasing means hereinbeiore described.

The thermal timing element which I now prefer to use includes a bimetal element IEI, of substantially U-shape, which has a contact member I83 mounted thereon at its outer end and which has its legs connected to and supported by two short bimetal strips I65 and IE1, which bimetal strips tend to warp in a direction opposite to that in which the bimetal element IGI will warp upon. change of temperature. I thereby provide a position-compensating means for the bimetal timing element ISI. This bimetal element, and particularly the strips I65 and IE1, is so supported on an adjustable pivot support I98 that the two strips I65 and I61 are insulated relatively to each other and have connected thereto circuit wires I69 and HI, respectively, whose connec tion and use will shortly be set forth. Means for Varying the initial position of member I6I may include a bar I13 (see Fig. 12) secured to the pivotal support and engaged by an adjusting screw I15, which screw extends through the trout wall of the casing and has an adjusting knob I'll secured thereon, by means of which an operator may cause slight turning movement of the support so as to vary the position of the supporting shaft I19, which may be seen by reference to Figs. 1, 6 and 12 of the drawings.

The intermediate contact member I91 which, as has already been stated, is supported by a spring bar I09, has connected therewith a relatively rigid extension bar I8I moving in a slot I83 in the base 23. A latch or locking lever I85 is pivotally supported intermediate its ends on a pivot pin I81 (see particularly Fig. 2 of the drawings) one end of arm I95 being adapted to be engaged by the depending end of portion IBI while its other end is adapted to engage a projection I88 on latch constituted by a pivotally mounted latch arm I89 which may turn on a pivot pin I9I and which has a tubular member I93 mounted thereon at the other end thereof, which tubular member I93, of electric-insulating material, may be engaged by the .bimetal bar IGI under certain conditions of its operation and caused to move in a counterclockwise direction, as seen in Fig. 2 of the drawings; A small coil spring I95 has one end connected to a pin fixed on the base 23 and the other end connected to a pin I81 extending upwardly from the bar I85, which bar is located below the base 28, the pin I81 .moving in a slot I98 in the base 23. I provide also a second coil spring 20I extending between the pin I91 and a pin 203, which pin is riveted into arm I89, extends upwardly through a slot 205. in the base 28, the effect of these springs I85 and EM being to hold thearms I50 and 588 in substantially the relative positions shown in Fig. 2 of the drawings.

Additional means for compensation for increase in temperature of the toaster structure-whereby the operation of bimetal member I8I will be such as to cause the toaster to produce similarly toasted slices of bread irrespective of change in temperature of the toaster, may include a bimetal bar 201 which has one end thereof supported on a relatively rigid bar-208 which has its other end secured to and against the bottom surface of base 28 adjacent one of the openings therein hereinbefore described, the member 208 having a lateral lug located against the under surface of base 28 and firmly held by a machine screw 2 and the usual nut thereon. The bimetal bar 201 carries a short machine screw 2 I 2 at its outer or movable end which may be held in any desired position and which is adapted toengage the free or movable end of a spring bar 2I2 having acontact member 2I5 at its outer end in such position as to be engageable by the contact member 158 on the bimetal element III.

I may provide an intermediate adjusting screw 2I8 on the bimetal bar 201, but no claim is made in the present application to this feature of my invention since it is disclosed and claimed in my copending application, Serial No. 20,110, flied May 6, 1935, and assigned to the same assigneeas is the present application.

Front and rear handles 2 may be provided to permit carrying the toaster.

Referring now to Fig. 12 of the drawings which shows the diagram of connections which I may use, I have illustrated a source of supply of electric energy as constituted by supply circuit conductors 2H and 2I8 and it is to be understood that suitable connecting means such as a twin conductor cord may be utilized in a manner well known in the art and as indicated by numeral 2 I 8 in Figs. 1' and 3 of the drawings. As has already been stated hereinbefore, the heating elements 85 may be connected in parallel circuit relation and one of the terminal rods as for example 45, may be connected to supply circuit conductor 2". One terminal of the latch release coil I48 is also connected to supply circuit conductor 2". The other terminal rod 41 is connected by a conductor 22I to one terminal of the bimetal timing element I6I and while I have shown it as being connected to bimetal element I81, it is to be understood that this is schematic only and that it may be suitably connected to a fixed part of the supporting means for this bimetal timer. Rod 41 is also connected to fixed contact terminal I05 as by means of a conductor 228.

The second compensating bimetal strip I85 is connected by a conductor 225 to the contact member I01 while the movable contact member II I on arm 8 is connected by a conductor 221 to the other supply circuit conductor M8. The other terminal of coil I48 ot-the electromagnetic latch release is connected through a conductor 228 to contact bar 2 I 8, which contact bar carries contact member 2I5.

Let it be assumed that it is'desired to toast two slices of bread which are dropped in through the openings in the casing to rest upon the bread slice supports 08, it being understood that suitable electrical connections have been made so that the" heating elements may be energized. The operator presses downwardly upon knob 91, moving it downwardly as far as it will go, when hook member I45 of latch arm I engages the edge of hardened plate I45 as hereinbefore set forth. The downward movement of the bread slice supports and of the mechanism connected therewith,

and particularly of the switch actuating plate I0 I, causes turning movement of switch arm H8 in a clockwise direction, as seen in Fig. 6 or the drawings, whereby contact I I I is caused to engage contact member I 01, which contact member I01 is also moved slightly toward fixed contact member I05, but not to such an extent as to operatively engage the same. Engagement of contacts I01 and I05 is prevented at this time by the biasing spring I08 and the engagement of the depending end of extension I8I with one end of arm I85. It will be noted by reference to Fig. 12 of the drawings that turning movement of arm I85 on its pivot is prevented because of the engagement of 151;: other end thereof with lug I88 on latch arm The downward movement of the bread slice supports by pressure on the handle 91 has not only moved the slices of bread into the casing and into toasting position therein, but has also effected closure of an energizing circuit traceable as follows: From supply circuit conductor 2 l1 through the plurality of heating elements 35, through conductor 22l, through bimetal bar 161 and from there through the bimetal bar I8I of U-shape, through bimetal bar i65, conductor 225, to contact member I01, to contact member I I I and from there through conductor 221 to the other supply circuit conductor 2 I8. This energizes the heating elements 35 which therefore effect toasting of the slices of bread. At the same time an auxiliary heating circuit for the thermal timer is provided, which in this case includes the bimetal member "I itself and the design and construction thereof is such that upon being heated by reason of the passage of current therethrough, it will warp in a counterclockwise direction as seen in Figs. 2 and 12 of the drawings. its design and construction is further such that the amount of energy available in the heating circuit is sufilcient to cause it to move quite rapidly so that it will, in a relatively short time, engage insulating tube I88 and cause a turning movement of latch arm I88 in a counterclockwise direction, thereby releasing arm I85, which also turns in a counterclockwise direction on its pivot to permit further movement of arm II3, contact III thereon and of contact member I01 toward and into engagement with fixed contact member I05. The spring I04, of substantially U-shape, on the switch actuating plate resiliently biases the switch arm H3 toward not only the intermediate contact member I01, but tends to bias this contact in a direction to engage fixed contact member I05, which cult through the plurality of bimetal bars and particularly through bimetal member IBI. This latter therefore starts to cool and now moves or warps in a clockwise direction or in general, in a direction opposite to that in which it moved at first. This returning warping movement continues with cooling oi this bimetal element until the contact member i 63 thereon engages contact member M on the thermally-controlled spring bar RIB, the engagement of. these two contact rheinbers resulting in energizing coil I49 of the eiectromagnetic release means and upward movementoi latch releasing rod I51 which engages the upper end of arm HI, moving it slightly in a counterclockwise direction to cause release oi the shoulder or book I43, the coil spring I31 then returning all of the parts to the positions shown in Figs. casement of contacts I63 and 2l5 at the beginning oi a toasting operation doesnot prevent latching by latch Ml because rod I51 overlies this latch when coil 9 is energized. 'And upon separation or these contacts, armature I53 and rod it! can drop down to the position shown in Figure 12 without alfecting the latch due to the pivotal mounting of rod I51.

it may be here stated that the intermediate positions oi the two movable contact members I01 and tilt are shown particularly in Fig. 7 of the drawings, while Fig.

where they are all in engagement with each other and the thermal energizing circuit of the bimetal timing element has been short circuited.

The bimetal element 201, as has already been stated, extends upwardly into the lower part of the heating chamber (as will be seen more particularly by reference to Fig. 1 of the drawings) so that it will respond to variations in temperature oi the toaster assembly structure or casing, but this is not the only location where it may be placed and it may also be located in other places so long as it will readily follow the toaster temperature. The design oi bimetal bar 201 and its arrangement is such that it will tend to move in a cloclrwise direction (as seen in Fig. 5 of the drawings) so that deenergization of the heating circuit and return of the bread slice supports to non-toasting position will be eiiected sooner when the temperature of the toaster structure or casing is hot than when it is cold. i have found it easily possible to compensate for increase in temperature oi the toaster structure by the use of the bimetal element 201 and the modifying screw 2 I6 so that once properly adjusted, toast of the desired type or'degree may be obtained irrespective oi temperature variation of the toaster resulting from either intermittent or substantially continucus use of-the master to toast successive slices oi bread, It is of course obvious that the bimetal supporting members I65 and I61 aid in securing this uniform toasting operation and it is to be understood that I may vary the length or the strips tit and i 61 as may be necessary in order to obtain the desired results.

While I have thus far described a thermal energizing circuit including the bimetal timing element itself, I desire it to be understood that I do not desire to be limited thereto and I have illustrated a modification of this part of my invention in Fig. 13 where a bimetal bar 235 may be employed instead of the bimetal member |6I of U- shape. rprefer to support the bimetal bar 235 by a short bimetal bar 231 which is suitably secured to one end of bar 235 in such manner as to oppose it, 6 and 9 of the drawings. En

B or the drawings shows the rinai positions of the three contact members to a certain extent the warping action thereof under a given change or temperature. The heating circuit may comprise a coil 239 of wire of a suitable ohmic resistance, which coil of wire has one end thereof connected to the bimetal bar 231,

so as to energize the same and permit a contact member 2 on the movable end thereof to operate in the same manner as was hereinbefore described for contact member I63 on the bimetal element I0i.

fills has already been hereinbefore stated, devices of this kind have been built by me and I have found it easy to obtain successive slices of bread toasted to substantially the same degree irrespective of the'temperature variations of the toaster caused by intermissions of lesser or greater length between successive operations.

It will be noted that the bimetal timing element is insulated to a certain degree from the heating elements so as not to be unduly affected thereby, nor to respond too great a degree thereto. The movements of the bimetal timing element are cyclic in that the bimetal element, when first thermally energized, moves in one direction, .mechanically engages a latch-releasing means whereby the heating circuit closely associated therewith is deenergi'zed, as by short circuiting the same, after which the timing element cools and warps or moves in the reverse or opposite direction, toward the end of which opposite or reverse movement it engages a contact member which cooperates therewith to close an energizing circuit through the coil of an electromagnetic latch-releasing means efiective to cause return of the movable parts to their initial inoperative positions. The length of time of a cooking operation therefore depends upon the time required for the main thermal element to warp or move in one direction and then to warp or move in the other direction to substantially its original position. It is therefore possible to use a single main bimetal element to control a cooking device used for short-time repetitive cycle operation and to obtain proper control of the length of time of each operation, when combined with a compensating means, irrespective of the temperature rise or fall of the toaster frame and easing.

While I have shown and described a specific form of device embodying my invention, I do not desire to be limited thereto, but that all modifications covered by the appended claims shall be included, the claims to be limited only by the prior art.

I claim as my invention:

1. In a. toaster, the combination with an electrio heating element, a control switch for the heating element spring biased to open position and a latch for holding the switch in closed position, of means including a bimetal element for effecting release of the latch, manually actuable means for closing the control switch and latching it in closed position and for causing the bimetal element to be traversed by an electric current and warp in one direction, means actuated by the bimetal element/in its movement in said one direction to electrically short circuit said bimetal element and cause it to move in an opposite direction and means operatively engaged by the bimetal element during its movement in the opposite direction and cooperating therewith to effect release of the latch and opening of the switch.

2. A. toaster comprising in combination, an electric heating element, a bimetal member, a heating circuit for the bimetal member, a switch for the heating element and the heating circuit spring-biased to open position, a normally open shunt for the heating circuit, manually actuable means to efiectclosing of the switch, a latch to hold the switch closed, a circuit comprising an electromagnetically actuated latch-releasing means, means mechanically actuated by the bimetal member in its movement in a certain direction to effect closing of the shunt for the heating circuit and a return movement of the bimetal member, a temperature responsive support for the bimetal element tending to reduce its movement in said certain direction with increase of temperature of the toaster, and means engaged by the bimetal member during its return movement to effect energization of the circuit comprising the latch-releasing means and deenergization of the electric heating element.

3. A toaster comprising in combination, an electric heating element, a bimetal member, a heating circuit for the bimetal member, a switch for the heating element and the heating circuit spring-biased to open position, a normally open shunt for the heating circuit, manually actuable means to effect closing of the switch, a latch to hold the switch closed, a circuit comprising an electromagnetically-actuated latch-releasing means, means mechanically actuated by the bimetal member in its movement in a certain direction to effect closing of the shunt for the heating circuit and a return movement or the bimetal member, and means engaged by the bimetal member during its return movement to effect energization of the circuit comprising the latchreleasing means and deenergization of the electric heating element, said last said means including a bimetal element responsive to toaster temperature, whereby the length of time of a toasting operation varies inversely with the toaster temperature.

4. A toaster comprising in combination, an electric heating element, a bimetal member, a heating circuit for the bimetal member, a switch for the heating element and the heating circuit spring-biased to open position, a normally open shunt for the heating circuit, manually actuable means to effect closing of the switch, a latch to holdthe switch closed, a. circuit comprising an electromagnetically-actuated latch-releasing means, means mechanically actuated by the bimetal member in its movement in a certain direction to effect closing of the shunt for the heating circuit and a return movement of the bimetal member, and means engaged by the bimetal member during its return movement to effect energization of the circuit comprising the latchreleasing means and deenergization of the electric heating element, said last said means including a contact member in the circuit comprising the latch release means, and a bimetallic member controlling the position of the contact member responsive to toaster temperature and effective to reduce the length of time to energize the latch-releasing means with increase of toaster temperature.

5'. A toaster comprising in combination, a frame, a fixed contact member thereon, an intermediate contact member spring-biased out of engagement with the fixed contact member, a first latch for holding the intermediate contact member out of engagement with the fixed contact member, a pivotally mounted outer contact member, a bimetal timing element, a heating circuit for the bimetal element, a main heating element for the toaster, an electrical connection between one terminal of the main heating eiement. the fixed contact member and one terminal of the heating circuit for the bimetal member, an electrical connection between the other terminal of the heating circuit for the bimetal member and the intermediate contact member, manually-operable means to cause the outer contact member to engage the intermediate contact member to thereby simultaneously energize the heating circuit for the bimetal member and the main heating element and cause the bimetal member to warp in one direction, a second latch to hold the manually-operable means in operated position, means whereby the warping bimetal member effects release of the first latch for the intermediate contact member to cause the same to engage the fixed contact member and thereby short circuit the heating circuit for the bimetal member and cause the bimetal member to warp in the opposite direction, a circuit comprising an electromagnetic release means for the second latch and a contact member therefor engageable by the bimetal member during its movement in the opposite direction to effect energization of the release means for the second latch and deenergization of the main heating element.

6. A device as set forth in claim 5 which includes a bimetal element responsive to toaster temperature to shift the position of the last named contact member, to cause deenergization of the main heating element to be effected in a shorter time upon temperature increase of the toaster.

7. A device as set forth in claim 5 in which the bimetal member is of U-shape and constitutes its own heating circuit.

8. A toaster comprising in combination, an electric heating element, a control switch therefor, a bread slice support, a single means for biasing the control switch to open position and the bread slice support to non-toasting position, a manually-actuable means to effect closing of the control switch and to move the bread slice support to toasting'position and to latch them in such positions and latch-releasing means including an electromagnetically movable member, a bimetal element of U-shape, supporting means including contact members operatively connected to the open end, of the bimetal element, an electric circuit through the bimetal element controlled by the control switch to cause the bimetal element to move in one direction, means mechanically engaged by the bimetal element during its movement in one direction to effect deenergization of the electric circuit through the bimetal element and cause a return movement of the bi-' metal element in the reverse direction and means engaged by the bimetal element in its return movement to close the circuit for the electromagnetically movable member and effect release of the latch.

9. In a toaster, the combination with an electric heating element, a movable bread slice sup port biased to non-toasting position, a control switch for the heating element biased to open position, a latch for holding the support in toasting position and the control switch in closed position and manual means for moving the support into toasting position and the control switch into closed position to be held therein by the latch, of means including a bimetal element of U-shape for effecting release of the latch, means whereby actuation of the manual means causes a current to traverse the bimetal element and efl'ect movement of a part thereof in one direciii iii

hit

till! iiiil bit of said first strip as the temperature or said comticn, ineans mechanically actuated by the bimetal element in its movement to electrically short circuit itself and cause it to move in the opposite direction and an electric latch-releasing circuit closed by the opposite movement of the bimetal element.

iii, Ina toaster, the combination with an electric heating element, a control switch therefor, a bread slice support. a single means for biasing the switch to open position and the bread support to non-toasting position and a latch for holding the switch in closed position and the bread support in toasting position, of a thermally-actuable timing means to eflect release of the latch including a bimetal bar of U-shape electrically connected in series circuit with the heating element, manual means ior effecting simultaneous energization of the electric heating element and the bimetal bar of U-shape to cause the latter to warp in one direction, means actuated mechanically by the bimetal bar in its movement in said one direction to short circuit the bimetal element and cause it to warp in a reverse direction and an electric latch-release circuit closed by the reverse movement of the biin-etal bar.

iii. A toaster comprising, in combination, a irame, a main heating element and a fixed contact on the frame, an intermediate contact supported from the frame and spring-biased out or engagement with the fixed contact, a pivotally mounted outer contact. a bimetal bar, of U-shape, conductors electrically connecting one terminal oi the main heating element with the fixed contact and one leg of the bimetal bar of U-shape, an electrical connection between the other leg or the bimetal bar or U-shape and the intermediate contact, manually operable means to cause the outer contact to engage the intermediate contact to thereby simultaneously enerrrise the main heating element and the bimetal bar, a iirst latch to hold the manually operable means in operated position, a second latch to hold the intermediate contact out of engagement iiiiiiiii the ilxecl contact, means mechanically actuated by the energized bimetal bar moving in one direction to release said second latch permit engagement of the intermediate and the tired contact to electrically short circuit the bimetal bar and cause it to move in the Opposite direction and an electric circuit closed by the bimetal bar in its movement in the opposite direction to effect release of the first latch.

iii. in an automatic toaster, two bimetallic heating and cooling to measure a toasting interval, means for heating the second strip independent of the first strip and in proportion to the rise in temperature of the toaster during rapidly recurring toasting operations, and means ior causing said second strip in heating to progressively shorten successive toasting intervals.

- iii. In an automatic toaster, a toasting compartment including a source of heat, a timer including a bimetallic strip and a second source of heat, means for measuring a toastinginterval by heating said strip from said second source and by then cooling the strip, a second bimetallic strip arranged to receive heat from said compartment, and means including said second strip for progressively shortening successive toasting intervals measured by the heating and cooling partment rises.

14..In an automatic electric toaster having heating means, a main thermally-actuable element, controllable means for heating said element and allowing the same to cool, a second thermally-actuable element responsive to toaster temperature, and means controlled Jointly by said first element during cooling? thereof and by said second element to terminate a toasting operation.

15. The combination with cooking means, of a timer for establishing intervals of the cooking mally responsive timer member has cooled and i warped to a predetermined extent in the opposite direction and the auxiliary bimetal member has been heated by the cooking action to a given temperature, said auxiliary bimetal member being operative to shorten successive toasting intervals.

16. In an automatic electric toaster having toast heating means, timing means comprising a thermally actuable element, a, controllable heater for said element, and a thermally responsive device subject to heat from the toast heating means and means controlled jointly by said thermally actuable element during cooling thereof and by said thermally responsive device to terminate a toasting operation.

it. An automatic electric toaster comprising a main and an auxiliary electric heater, 9. thermal timing means including a bimetal bar in heat receiving relation with the auxiliary heater, three contact members normally yieldingly biased out or. engagement with each other, means to cause electrical contact oi two of said contact members and cause energization of the main and the auxiliary heater to initiate a toasting operation and the operation or the thermal timing means, means including the blmetal bar i'or causing electrical contact oi all of said contact members when the bimetal bar has been heated to a predetermined high temperature to substantially deenergize said auxiliary heater, said bimetal bar then cooling and causing disengagement of all 01' said contact members from each other when it has cooled to a predetermined lower temperature to terminate a toasting operation.

18. An automatic electric toaster comprising a toast heater, a thermal timing device including a bimetal element of U-shape, three contact members normally yieldingly biased out oi! engagement with each other, means to cause two of said contact members to electrically engage each other to effect current flow through the toast heater and through the bimetal element to initiate the operation of th toaster and of the thermal timing device, means including said himetal element i'or effecting electrical engagement oi all of said contact members when the bimetal element has been heated to a predetermined high temperature to substantially stop current flow through the bimetal element and means including said bimetal element for causing electrical disengagement of all or said contact members when the bimetal element has cooled to a predetermined lower temperature to terminate astrip, means for releasing said carrier means by heating and cooling said strip, including heating means independent or the heating means in said toasting compartment, a second bimetallic strip arranged to receive heat from said toasting compartment and means including said second strip for changing the time interval measured by the first said strip.

MURRAY IRELAND. 

